The Cobalt Blue Tarantula (Cyaneopubescens) is a striking and captivating species, beloved by tarantula enthusiasts for its vibrant coloration and intriguing nature. When considering adding one of these stunning arachnids to your collection, understanding the differences between males and females is crucial. This guide provides you with five key facts to differentiate between male and female Cobalt Blue Tarantulas, helping you make informed decisions about care, lifespan, and overall expectations for your pet. Whether you are a seasoned tarantula keeper or a beginner, knowing these facts will enhance your ability to provide the best possible environment for your Cobalt Blue Tarantula.
Cobalt Blue Tarantula Male vs Female Fact 1: Size Differences
Size is often one of the most apparent differences between male and female Cobalt Blue Tarantulas, particularly as they mature. Generally, females tend to be larger and more robust than males, a common trait in many tarantula species. This size difference is not always immediately obvious in younger specimens but becomes increasingly apparent as they reach adulthood. Understanding these size variations can assist in estimating the tarantula’s age and potentially its sex, although other methods are more reliable for accurate sexing.
Male Cobalt Blue Tarantula Size
Male Cobalt Blue Tarantulas, when fully grown, typically reach a smaller size compared to their female counterparts. They often have a leg span that is slightly less, which can be a noticeable difference when placed side by side with a female. This smaller size is a direct result of their shorter lifespan, as they invest less energy in growth compared to females, who must reach a size sufficient to carry eggs. Recognizing this size difference is one of the preliminary steps in differentiating between the sexes.
Female Cobalt Blue Tarantula Size

Female Cobalt Blue Tarantulas are generally larger and more substantial. Their leg spans are typically greater than males, providing a more imposing presence. This size difference is crucial, as the female needs a larger body to carry and produce eggs. The greater size of females not only facilitates egg production but also contributes to their longer lifespans. Therefore, the size difference provides a significant clue about the sex of a Cobalt Blue Tarantula.
Cobalt Blue Tarantula Male vs Female Fact 2: Color Variation
The vibrant coloration of Cobalt Blue Tarantulas is one of their most alluring features. While both males and females display the striking blue hues, subtle variations exist. These differences are often related to the age and stage of the tarantula’s life cycle. Observing these nuances in color can provide another way to differentiate between the sexes, although it is less definitive than examining other physical traits.
Male Cobalt Blue Tarantula Coloration
Male Cobalt Blue Tarantulas often display a slightly different shade of blue, which can sometimes appear less intense than that of the females. Additionally, the males may exhibit color changes as they approach maturity and after their final molt. These color variations are often accompanied by other physical changes associated with sexual maturity, such as the development of tibial hooks on their front legs, used for mating. The color differences are subtle, making it necessary to consider other factors for definitive identification.
Female Cobalt Blue Tarantula Coloration

Female Cobalt Blue Tarantulas are known for their consistently bright and vibrant blue coloration. This rich color is usually more intense and uniformly distributed across their bodies. As females molt and mature, they retain this striking coloration, which is a key factor in their attractiveness as pets. The maintained vibrancy is an important visual cue for distinguishing females from males, who may experience some fading of their colors over time.
Cobalt Blue Tarantula Male vs Female Fact 3: Lifespan Differences
One of the most significant differences between male and female Cobalt Blue Tarantulas is their lifespan. Understanding these lifespan differences is important for long-term planning and care. The longevity gap impacts the decisions of prospective owners. The sex of the tarantula strongly influences how many years it can be expected to live.
Male Cobalt Blue Tarantula Lifespan
Male Cobalt Blue Tarantulas have a significantly shorter lifespan compared to females, typically living for only 2-3 years once they reach maturity. This shorter lifespan is due to their primary role in reproduction. Once males reach maturity, they focus on mating, which consumes a lot of their energy and resources. After mating, they often die, thus shortening their lifespan significantly. Knowing the expected lifespan allows keepers to plan for the tarantula’s lifecycle.
Female Cobalt Blue Tarantula Lifespan

Female Cobalt Blue Tarantulas have a much longer lifespan, which makes them a long-term commitment for tarantula keepers. Females can live for up to 12-15 years, providing many years of enjoyment. This extended lifespan is the result of their role in egg production and their slower metabolism. Their longevity also makes them a more valuable pet and provides an engaging educational opportunity about the life cycle of tarantulas.
Cobalt Blue Tarantula Male vs Female Fact 4: Physical Characteristics
Beyond size and color, specific physical characteristics can assist in sexing a Cobalt Blue Tarantula. Examining these traits is often more accurate than assessing size or color alone, especially in subadult tarantulas. These traits can give you a clear visual confirmation of the tarantula’s sex.
Male Cobalt Blue Tarantula Physical Traits
Mature male Cobalt Blue Tarantulas develop several distinctive physical traits. The most notable is the presence of tibial hooks on their front legs. These hooks are used to hold the female’s fangs during mating, allowing them to safely insert their pedipalps for sperm transfer. In addition to tibial hooks, males also have modified pedipalps, which are bulbous at the ends, used for storing sperm. Identifying these traits is the most reliable method to determine the sex of a Cobalt Blue Tarantula.
Female Cobalt Blue Tarantula Physical Traits

Female Cobalt Blue Tarantulas do not possess tibial hooks or modified pedipalps. The absence of these features is a definitive indicator of their sex. In addition to the absence of these traits, females have a spermatheca, a structure used to store sperm after mating. To identify the spermatheca, a molt can be examined under magnification to reveal this key trait. Careful observation of these traits, along with an assessment of size and color, ensures accurate sex identification.
Cobalt Blue Tarantula Male vs Female Fact 5: Behavior and Temperament
Differences in behavior and temperament between male and female Cobalt Blue Tarantulas can also provide insights into their sex. While both sexes can be defensive, their behaviors often differ, especially concerning mating and reproduction. Knowing these differences can help keepers understand their pet’s needs better.
Male Cobalt Blue Tarantula Behavior
Male Cobalt Blue Tarantulas often become restless and more active as they reach maturity. They may spend a considerable amount of time wandering in their enclosure. This behavior is often associated with their search for a mate. They may also become less inclined to eat. Once they mature, males often exhibit a strong urge to mate, which can make them more vulnerable if not handled carefully. Understanding this change helps in providing the right environment.
Female Cobalt Blue Tarantula Behavior

Female Cobalt Blue Tarantulas generally have a more stable temperament, though they can be defensive. They tend to be less active and spend more time in their burrows or hiding places. They also have a strong feeding response, which is necessary to support their growth and egg production. Females that are well-fed and in a suitable environment are less likely to display defensive behaviors, making them relatively easier to care for. Providing a proper habitat is crucial for their overall well-being and behavior.
In conclusion, accurately sexing a Cobalt Blue Tarantula requires careful observation and understanding of several key differences. From size and coloration to lifespan, physical characteristics, and behavior, each factor provides valuable clues. Knowing these differences empowers tarantula keepers to provide the best care and make informed decisions about their pets. By understanding the distinctions, you can better appreciate and enjoy the unique qualities of your Cobalt Blue Tarantula, whether male or female. Choosing a Cobalt Blue tarantula can be a rewarding experience for any tarantula enthusiast, and with the right knowledge, you can provide the best possible care for your fascinating arachnid.
